Hydrodynamic transmission



Sept. 9, 1952 J JANDASEK 2,609,706

HYDRODYNAMIC TRANSMISSION Filed April 15, 1948 2 SHEETS-SHEET 1 INVENTOR. Jseyi Jlzwd'aaei.

BY I W V- 19770F/V1776Y Patented Sept. 9, 1952 2,609,706 HYDRODYNAMIC TRANSMISSION Joseph Jandasek, Highland Park, Mich., assignor to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Application April 15, 1948, Serial No. 21,140

33 Claims. 1

This invention relates to hydrodynamic transmissions and refers more particularly to improvements in variable speed ratio drives for motor vehicles. While particularly adapted for motor vehicle drive, still, this invention can be used in any mechanism Where it is desired to automatically vary the speed ratio drive between. the driving and driven elements.

It is an object of this invention to provide a combined. hydraulic and mechanical transmission that is automatic in operation, simple in design, and fully capable of providing adequate variation in speed ratio drive to efliciently and satisfactorily operate the conventional motor vehicle under all driving conditions.

More particularly my invention has to do with an improved and simplified power transmission comprising a hydraulic torque converter unit and associated mechanical gearing, so constructed and arranged as to automatically vary the speed ratio drive between the driving and the driven elements, the variations in speed ratio drive during normal drive occurring without the manual operation of a clutch pedal or any other speed ratio control means.

t is a further objector this invention to provide a motor vehicle transmission comprising a hydraulic torque converter unit and an associated variable speed gear unit wherein means are provided to initiate acceleration of the vehicle through a combined fluid and mechanical,

low speed, high torque multiplying underdrive train, after which means automatically effect a loclnout of the torque converter unit and continue the accelerating drive through a complete- .ly mechanical underdrive train that is adapted to be automatically upshifted to a positive direct drive for cruising purposes. The cruising direct drive train by-passes the torque converter unit and the variable speed gear unit so as to provide a slipless, efficient, direct drive that is particstarting, low speed, accelerating underdrive previously referred to.

The automatic shifting between the starting underdrive and the direct drive ratios is intended to be controlled by means responsive to vehicle speed and torque demand but other forms of governor'means might be used to'accomplish the automatic shifts. Byvirtue of the automatic shifts between the initial, low speed, accelerating, underdrive, the mechanical, high speed, underdrive and the positive direct drive, there is provided a completely automatic device for accomplishing all variations in speed ratio drive required for normal vehicle operation.

It is a further object of this invention to provide a hydrodynamic transmission having means 'for connecting the driving input shaft to the driven output shaft, through a completely me chanical speed reduction gear train that provides a positive drive operable as a coasting brake as Well as an emergency low gear underdrive. This drive also by-passes the torque converter unit and eliminates the possibility of slip between the converter elements. It is desirable to provide control means to automatically shift this emergency low gear drive into the low speed, accelerating, underdrive when the vehicle speed and torque demand attain certain predetermined values. This shift will prevent engine stall when the vehicle is brought to rest with the drive selector positioned in the emergency low speed driving ratio.

It is a further object of. this invention to supply a hydrodynamic transmission with means providing a combination fluid and mechanical, low speed, high torque multiplication underdrive for initial acceleration, which drive is adapted to be automatically shifted into apositive, high speed, mechanical underdrive when the torque multiplying effect of the hydraulic unit begins to be less effective. By reason of this shift into the positive underdrive, prior to the time the hydraulic torque converter unit begins to function as a fluid coupling, a more eincient power transmission unit is provided due to the con verter unit being used only when the torque multiplying effect is most effective and most efficient. Furthermore, due to the step-by-step shifts from the initial accelerating underdrive into the cruising direct drive, there is provided a transmission unit characterized by smooth, automatic changes in speed ratio drive.

It is a further object of this invention to provide a hydrodynamic transmission of simple (19- sign that includes a combination hydraulic and .reaction wheels H and H3 respectively.

aeoojoe mechanical, high torque multiplication, starting 'underdrive for low speed acceleration, a positive,

underdrive adapted to provide a coastin braize,

and a reverse drive.

It is a further object of thisinvention to pro-- vide a hydrodynamic transmission with a simpli fied, highly flexible control system that does notclutch or requires. manually operated friction the like.

It is a further object of this invention to provide a novel control system for this transmission wherein manually operated drive selector means overrule the automatic speed ratiocontrcl means so as to provide means which will retain the transmission inany selected gear ratio;

It is a further object of this invention to provide an improved, simplified, hydrodynamic transmission that is particularly adapted for the utilizationof turbo-braking. Turbo-braking in this construction is'primarily designed to assist or supplement the engine braking- 7 available through the emergency low gear drive train.

Other objects and advantages of this invention will be apparent from a consideration of the at,- tached specification and'related drawings where- Fig. 1 is a sectional elevation View showing power transmission which embodies a torque converter in combination with aplanetary gear type change speed unit;

Fig. 2 is-a fragmentary-sectional elevational view taken along the line 2-2 of Fig. l disclosing the type of one-way or overrunning brake construction used between'the converter guide wheels and the transmission housing;

Fig. 3 is a diagrammatic view of the transmission-and a control system therefor, the transmission being shownconditioned for the transmission of direct drive; and

Fig. dis a: fragmentary sectional elevational view of the by-pass control valve for effecting theautornatic shifts between the emergency low chanical change speed unit 13. Thereference numeral [0 represents an end portion of a power driven shaft, such as the engine crankshaft of a motor vehicle, this shaft It] being connected at E i to the flywheel I2. The flywheel l2 carries the torque converter casing is within which are mounted theconverter components, namely, the impeller member M, the turbine member !5, and the primary and secondary guide membersT 1or 1e vaned impeller member M is fixedly connected to the converter casing l3 and is accordingly rotatably driven by the driving shaft I53. The vaned turbine member is drivingly connected to the forward end portion of a hollow shaft 'member 16 which shaft member is journalled on the intermediate shaft 38; subsequently described in detail. Primary and secondary guide wheels H and [8 are connected tothe transmission housing tfl through freewheeling or oneway brakesii and'22 respectively.

4 As clearly shown in Fig. 2, the one-way brake construction 2| comprises rollers Zia mounted within a cage member 2th. The cage member 251) is normally urged into drive transmitting position by means of a tension spring (not shown). Cam surfaces 23a formed on the peripheral surface of the housing sleeve member 23 cooperate with the brake-rollers fla and guide wheel hub portion fiato-permit one-way rotation of the guide wheel ll. The sleeve member 23 is splined to the transmission housing at 24.

The one-way brake connections between the guide wheels ii and I 8 and transmission housingpermit-theguide wheels tobe rotated forwardly by-the impeller M but prevent rotation' of the guide wheels in a reverse rotational direction. The guide wheels I? and [8 connected to the transmission housing 20 through the oneway brake connections provide the reaction means for the converter unit. By using a plurality of guidewheels, connected to the transmission housing 'through separate one-:way brakes, the efficiencyof 'the-converter unit-is improved, this feature" being clearIy explained in the patent to A. Coates,No. 1,760,480,-'dated--May' draulically operated control mechanisms asso-' ciated with this transmission. The, circulation of oil through the converter, by the engine driven pump 25, provides a' 'meansi; for -maintaining the converter full of oil whenever the engineis running, and, furthermore, this'circulation of fiuid thrioughthe converter: and lubrication system provides'a means' for cooling'the converter fluid. To further assist in'the cooling of the converter. fluid, fins 26 .are. provided .on; the exterior surface of the converter casing (3 so as to circulate air about the converter casing and thereby reduce the temperature ofthe 'fluid'wi'thin the converter c'asing.

The aforementioned intermediate shaft 303 has its forward end. portion supported byand connected to the crankshaft ldpthe isplined connection between these" members being indicated by'the numeral di. The rear end portion 'of shaft 39 encircles and is journalled on theforward end portion of the driven output shaft 45. Rotatably mounted on therear'portion of intermediate shaft 39 are three planetary gear trains indicated-by the numerals 3'1, 33, and 39 respectively. The forward gear traintl. provides means for obtaining reverse drive throughthe transmission. "The intermediate .gear-'train"-'38, in combination with the torque converter unit, provides means for obtaining a combination fluid and mechanical, high torque multiplying, ,low speed, accelerating underdrive adapted for initial acceleration. This gear train 38, in'combination with lock-up clutch D, also'p'rovides a means'for obtaining a positive, high speed underdrive which is 'adapted'to be automatically upshifted to :di= This same gear train provides-a drive to a fully mechanical, high speed, underdrive ratio adapted for accelerating purposes in the cruising speed range. The rear gear train 39 provides a coasting gearv for engine braking purposes as well as a'means for obtaining anfemerv44 to the output shaft 45.

gency low speed underdrive through the transmission. l i i l j Therear end portion of intermediate shaft 32 has annular member 35 splined thereto as indicated at 35. Member 35 is formed with gear teeth 4i which constitute the sun gear element of the rear planetary gear train 39. Mounted on the rear portion of member 35 are friction clutch elements 42, of direct drive clutch C, which elements are adapted to be engaged with cooperating clutch elements, 43 carried by the drumshaped extension 44 of the output shaft 45. Engagement of clutch elements 42 and 43 is effected through a hydraulically actuated piston member 46. When clutch elements 42 and 43 are engaged a direct drive is transmitted directly from the engine crankshaft I through intermediate shaft 30, clutch elements 42 and 43 and drum member When the engine is connected to the output shaft through this drive train, the transmission is conditioned for the normal, forward, cruising, direct drive. This drive provides slipless engine braking for the drive train by by-passing the torque converter unit A and the planetary gear trains of the change speed unit B.

Planetary geartrain 31 includesplanet'carrier 5| which is formed with an axially extending peripheral drum portion 5Ia adapted to be engaged by the braking band 52. Rctatably mounted on carrier 5| are a plurality of planet pinions 53. The teeth of pinions 53 mesh with the external teeth on the enlarged hub portion 33a of annular member 33. The annular member 33 has its hub portion 33a drivingly connected by splines 34 to the rearwardly projecting end portion of the turbine driven hollow shaft ISL The toothed portion 33a of annular member 33 constitutes the sun gear of the forward planetary gear train. The teeth of pinion 53 are also in meshing engagement with the internal teeth on drum member 55. Drum member 55 constitutes the annulus gear of the forward planetary gear train 31. The drum member 55, while forming a part of the forward planetary gear train 31 is supported by and forms a part of the planet carrier 6| of the intermediate planetary gear train 38 Planetary gear train 38 includes the planet carrier GI which is rotatably supported on the intermediate shaft 30 by means of hub portion 6Ia. Planet pinions E2, rotatably mounted on carrier BI, have teeth meshingly engaged with internal teeth on the rearwardly projecting drum portion 33b of annular member 33. This internally toothed portion 33b of member 33 forms the annulus gear of the intermediate planetary gear train 38., The teeth of pinions 52 also engage external teeth on the hub portion 64a of the rotatably supported drum member 64. Drum member 64 is rotatably supported on hub portion Blaiof planet carrier member 3|. The toothed hub portion 64a of drum 64 constitutes the sun gear of the intermediate planetary 38. Drum 64 has an axially extending peripheral flange 64b adapted to be engaged by the braking band 65.

Rear planetary gear train 39 includes the drum-like annulus member II which is rotatably supported by the radially extending wall portions Ila'and lie on the hub portion 6m of planet carrier BI and the output shaft drum member 44 respectively. Annulus member ll has an axially extending peripheral flange portion lIb adapted to be engaged by a braking band 12.

, Flange portion I II) carries internal teeth adapted .39. Planet pinions I4 are rotatably mounted on .theplanet carrier which is supported by and connected to the hub portion 6Ia of planet carrier Si by means of the spline connection 11. Planet carrier 75 isalso connected by bolts 38 to the drum shaped extension 44 of output shaft 45.

Thedirect drive clutch C includes the hy- ,draulically actuated piston 46, which is adapted to be moved forwardly in cylinder 93 to effect engagement of the friction clutch plates 42 and 43,; Piston 46 is normally held in a retracted,

- disengaged position by means of compression springs 85.

However, when the transmission is to be conditioned for, the transmission of direct drive from the engine crankshaft III to the output shaftu45, then pressure fluid is admitted to the cylinder 99, between the head of piston 46 and the inner wall of drum member 44, and this moves piston forwardly to compress springs 30 and engage the clutch discs 42 and 43. Engagement of, the direct drive friction clutch elements 42 and 43 occurs only, afterall planetary gear braking bands have been retracted to disengaged posi tions.

To, provide means for the transmission of a completely mechanical, high speed, underdrive, a

torque converter lock-up clutch mechanism D is associated with the intermediate planetary gear train 33. This lock-up clutch construction comprises the drum-like extension or spider I2l, formed on shaft 33, which extension is adapted to drivingly support the friction clutch discs I22. Intermedite planetary annular member 33 has wallportions which form a cylinder I21 within which a pressure fluid actuated piston I24 is adapted to be reciprocated. Drivingly mounted on the axially extending portion 33b of annular member 33, are friction clutch discs I26 which are adapted to be engaged with the clutch discs I22 when piston I24 is moved rearwardly by the admission of pressure fiuid into cylinder I21. Piston I24 is normally held in a forward, deac- I28. Clutch D is engaged by admitting pressure ,fiuidto the cylinder I21 and this shifts piston I24 rearwardly so as to engage clutch discs I22 and I26 and connect shafts I5 and 30 to thereby lock-up the impeller and turbine members of the torque converter A. Looking up the torque converter driving and driven elements in effect shifts the input drive for planetary gear train 38 from the turbine driven shaft It to the engine driven intermediate shaft 30 and thereby by-passes the torque converter unit. Upon engagement of clutch D drive is transmitted from driving shaft It to intermediate shaft 30, then through engaged clutch discs H2 and I26 to the internal teeth on the flange portion 33b of annular mem ber 33. These internal teeth on member 33b constitute an annulus gear and drive the planetary pinions 62 of the intermediate planetary gear train 36. Due to braking band being applied to drum 64, whenever drive is through planetary train 38, the sun gear 64a is fixed and the driven planet pinions 62 drive the planet carriers GI and i5 to thereby transmit a positive, high speed, underdrive through drum 44 to output shaft 45. It will be noted that with the interrotation by braking band 65, and annulus gear train "33.

acoavoe V member 33b=rotatably driven by-the'inte'rme'diate shaft as as 'a-result-of the torque converterdockup, a completely mechanical,=-positive,- underdrive is transmitted-to the output shaft' 55.

With drive selector'lever 8 i (see Fig- 3) positioned in Neutral,'thecontro1systemis so designed that the braking-hands of the three planetary gear trains 3751M?and' 'sa 11.. 1 1 disengaged positions and thedirect' drive clutch C and torque converter lock-up clutchD-are-b'oth maintained in ad-isengagedcondition. 'Accordingly, drive cannot --be-'-transmitted"from the engine crankshaft! e to the output shaft 35. If The control system shown in Fig; 3 is-so arranged that whenever anyone planetary braking band .is applied, then the other bandsare releas'edgexcept band in order to obtain turbo-braking to assist the low gear coa'stihgf brake, as will -be subsequently explained. 7

Operation of this transmission is as-follows:

For ordinary forward drive-the"drive 'selector lever B i, normally mounted on asteering column 82gis moved from the Neutral position to the position indicated as High. This: causes] linkshift the plunger i i-l of the manual control valve 9 5 to a position whereby pressure fluid from-the pump 25 is directed via conduits 29 and [42, into the upper portion of the intermediate planetary brake band cylinder 85. The admission oi' pres- 'sure fl'uid' into'the uppenportion of cylinder '85 depresses' the. piston-in the cylinder: and locks brake band 'ee about the drum 1 member 64': to therebyanchor-s'un gear member E la; against rotation. -'Anohoring gear 64a against rotation activates gear t'rain til. Whenever the vehicle is at a standstill, '-orduring initial acceleration,

speed and :torque -conditions-are such that the speed and torque responsive governor means 88, subsequently described in' detail, effects ener'gi'zation of each ofthe solenoids l llland lfillthat operate the control valvestii and IE9 respectively. Energizaticn "of these solenoids retracts the spring-pressed valveplungers 1% and l-efi to posie tions thatclose the control valves 89 and- 159. The closing of valves 89' and 159 prevents the ad- 'mission of pressure nuid to either of the clutch mechanismsG- or- D. I As a resultof the activation of intermediate *gear train SB-by the application of brake band te'and the disengagement of both clutch mechanisms C and'D, dueto the energization of solenoids H6 and let respectively, the transmission unit is conditioned for thetransmission of a combination hydraulic and mechani- "5! is drivingly connected to the planet-carrier member 15 of the rear planetary train 39 and to theoutput shaft drum member M,- a combination hydraulic and mechanical, high torque m'ultiplyingylow speed underdrive; particularly J adapted for initial vehicleaccelera'tion, is transmitted when'itis desired to manually apply an additional;

, '25 age 83 to actuate the shift rail'member lillaand vehicle. multiplication' period the guide"wheels l1 and 1B 'from'the engine crankshaft 10 through the-converter unit A and planetary gearing B to the output shaft 45. 'It Will-benoted thatthis low-speed, accelerating, underdrive' is a combination fluid and mechanical torque multiplying drive for the torquemultiplying' effect of theconverter unit is amplified by the torquemultiplying 'efiect of 'the intermediate planetary gear train 33 and the product of these two-torque multiplications is transmitted to the output shaft lii-to provide the necessary accelerating power for the starting low speed drive.

'On initial acceleration through the" above- "described low speed underdrive" gear train; the converterimpeller Hl'isrotated in a counterclockwise direction by engine crankshaft 11c. The shaping of the blades of the impeller, turbine and guide wheels' of the converter unit is such that counterclockwise rotation of impeller A' 'directs the converter fluid against-the blades of the guide wheels M ami 18 in such a manner as to tend to rotate the guide wheels in a reverse or clockwise direction. 'Dueto the one-way brakes; 2| and 22,

between the guide wheelsand the sleeve extension 23 of the transmission housing 20,lthe. guide wheels are locked-up against reverse rotation and areaction eiiect is produced.whichmultipliesthe torque transmitted by the converterunit. LThis torque multiplication provides the accelerating power necessary for the starting drive of a motor During the major portion of this torque arelocked-up by the brakes 2i and 22in a substantially stationary condition.- As vehicle speed increases and the torque demand begins to decrease, the speeds of the converter impeller is and the runneri 5 tend to-attain substantially the same value. .As the sp'eeds of these members begin to approach the same'value, the reaction forces directedagainst theguide wheel blades gradually disappear and the impelled fluid-within 1 the converter begins to'drive the guide-wheels forwardly lira counterclockwise direction. The

' forward drive of the guide wheels isa'step-by-step process as first one guide wheel will'be picked up .by'the impelled converter fluid and rotated forwardly and subsequently the'other guidewheel will be picked up by the converter fluid and rotated forwardly. "The use of a plurality of con- 50 verter guide wheels improves the 'efficiency and operating characteristics of the converter unit.

I If the accelerating drive was continued through the above described startingdrive train, eventually the impeller,'turbine and-guide wheels would all be rotating in the-same direction at sub- 1 stantially the same speed and the converter unit would be functioning as a simple' fluid coupling. 'However, due'to' the fact that the torqucgmultiply- 'ing eifect of the converter unit decreases rapidly with increase in speed of the driven turbine memher It and also due to the fact that the eiiiciency of the converter unit-drops-oi'l at high speed, this transmission provides I means adapted to automatically efiect engagement of the torque conQ verterlock-up clutch D, after the torque multiplying-effect of the converter unit has been most advantageously utilizedbutprior to the time the converter'unit would begin to function as a simple ffluid coupling, so that th'ereafterthe accelerating underdrive is transmitted directly from thelinput shaft It, via shaft to, to'the input annulus memher 331) of the planetary gear train- 38. With the converter unit locked out of the drive train by the engagement of' clutch D, the second step of the accelerating underdrive is I then transmitted through a high speed, completely mechanical, underdrive train. This latter drive is adapted to be automatically upshifted into direct drive, when the speed and torque conditions attain predetermined values, as will be subsequently described.

Normally when the vehicle speed in the starting, low speed, high torque multiplication underdrive reaches a value of between 20 to 25 miles per hour, the torque multiplying effect, as well as the efliciency of the torque converter unit will have been reduced to a point where it is desirable .to lock-up the torque converter unit and continue the acceleration of the vehicle through the positive, high speed, underdrive. This automatic shift from the starting, low speed underdrive into the positive high speed underdrive is effected through the speed and torque responsive governor means 88, substantially described in detail, which controls ,energization of both automatic control valves 89 and I59. At the speed and torque condition when it is desirable to shift from the low speed to the high speed underdrive the governor means 88 causes a de-energization of the solenoid I60 and this permits spring IBI to raise valve plunger I56 to an open valve position so as to allow pressure fiuid to be directed from pump 25 through conduits 28 and Ill into the lock-up clutch cylinder I2I.j Admission of pressure fluid into cylinder I2'I effects engagement of the clutch discs I22 and I26 and locks together the impeller and turbine members of thetorque converter unit so that a positive underdrive, adaptedfor high speed acceleration, is now transmitted from input shaft I through intermediate shaft 39, engaged clutch D, and gear train 38 to the output shaft 45. It is obvious that, by starting acceleration through the series connected torque converter unit and accelerating underdrive gear train,,to provide high torque multiplication and a smooth start, and then subsequently locking out the torque converter unit after the major benefit of the converter unit has been substantially utilized, there is provided a most efficient and satisfactory underdrive arrangement.

The acceleration of the vehicle at the higher speeds iscontinued through the completely mechanical, high speed, underdrive train until such a point is reached that it is; desirable to effect an automatic upshift into direct drive. Somewhere between approximately 25and 60 miles per hour thespeed andtorque conditions will be such that the upshift to direct drive will be advantageous. At this point the governor means 88 causesfa deenergization of the'solenoid III] which then permits spring I I I to raise valve plunger I96 so as to open valve 89. Opening valve 89 directs pressure fluid from pump 25 through conduits 28, 81 and 81a into the direct drive clutch cylinder 99 so as to cause engagement of clutch C and directly connect shaft 39 to the output shaft 45 through clutch C and drum member 44. Opening valve 89 not only engages clutch C but in addition pressure fluid is directedthrough conduits 28, 81 and 81b into the underside' of intermediate brake band piston85 was to effect a release of the heremember 44, and

If while operating in direct drive, the vehicle speedis substantially reduced and the torque demand increased, then the speed and torque responsive governor means 88 effects energization of solenoid III] and a closing of the direct drive clutch control valve 89. Closing of valve 89 shuts off the supply of pressure fluid to the direct drive clutch cylinder 90 and to the underside of intermediate brake band cylinder 85. Closing valve 89 also uncovers drain port 95 which then drains the pressure fluid from the underside of cylinder 85 and from the direct drive clutch cylinder at.-

tary sun gear drum member 64b. As a result of 7 this shift in drive transmitting trains, caused by the governor controlled closing of valve 89, there is effected an automatic downshift from direct drive to the high speed, accelerating, underdrive. This automatic downshift is completely controlled by the speed and torque responsive governor means 89. It will be noted that when'operating in direct drive both control valves 89 and I59 are open and both clutches C and D are engaged. Drive is not transmitted through the underdrive gear train 38 because the underdrive braking band 65 is not applied therefore there is no reaction point for this gear train. By retaining the clutch D engaged during direct drive the transmission is always conditioned for the downshift to the high speed, positively connected underdrive.

If, while operating in the cruising direct drive ratio, the vehicle operator desires to rapidly accelerate the vehicle, a completely mechanical, high-speed, accelerating, underdrive is available which may be manually activated to accomplish a smooth acceleration in the cruising speed range. This high speed, accelerating, underdrive is designed to be activated atany time and is specifically intended to be brought into operation prior to the time that a reduction in vehicle speed would cause the speed and torque responsive governor means 88 to automatically effect a downshift from direct drive to the high speed, acceleratingunderdrive previously described. To effect the kickdown from direct drive to the high speed, accelerating, underdrive, the vehicle operator need merely depress the throttle controlmember to its limit whereupon the stud B6, on the thrntt e control pedal 86, will actuate the linkage 9| so as to cause the linkage to overrule the governor means 88 and effect a closing of the valve 39. Closing valve 89 through manual actuation of linkage 9| disengages the direct drive clutch C and reapplies the intermediate planetary gear brake band 65 to the drum 64b in the same man ner as already explained with regard to the automatic closing of valve 89 by governor 88 during the automatic downshift from direct drive to the high speed, accelerating, underdrive.

This manually controlled kickdown from direct drive to the high speed accelerating underdrive is particularly advantageous in passing other motor vehicles when operating in the cruising speed range. Due to the kickdown drive train by-passing the torque converter unit there is no chance of racing the engine or creating a turbobraking effect on kickdown as might possibly result. from a high speed kickdown through the torque converter unit. It is obvious that when the depressed throttle control member 85 is reassayed...

vided the vehicle speed and torque demand are.

such as to condition governor 88f for suchna drive. If {conditions should changetso. that the governor means 88 causes valve 89 to.remain.closed,;after the throttle control 85 is..re1eased to.;terminate. the ,kickdovvn drive, then. the transmission. Will' continue to transmit'jdrive through the high-.

speed, acceleratingunderdrive, Theupshift from.

the highspeed, accelerating ,unde'rdrive back-to. direct drive- Will 'occur in the normal manner under the control of the;speed'and., torque .re..-.

sponsive. governor 88. If .While operating ,inth'e high'speed, .underdrivethe output shaft. speed should continue to drop and ,the torque .demand.

increase, then govcrn.or.38i..vvil1" close valve J58 and .this will efiecta downshift into theloyvspeed high; torque multiplying underdriven To 1 obtainlreverse drive through. this transmis-p, sion the vdrive selector lever ,8 I, isv moved to .the position, indicated as Reverse "and this' shifts,- rail member ,ll'i'l' rearvvardly' to a,.position,that. closes" offthe fiowof pressure fiuid throughivalve 84: and causes cam portion. I31 of rai1.|l3.i..-to.ac-, tuateithe followenlSfi so as. to loch-reverse band, Braking band 52 is of the self; energizing type and provides .the reaction. means forthereverse drivegear train 31. It is obvious. that the. otherlbraking bands; .for. the. planetary geartrainsfit and 39 are ixiretracted, disengaged positions at this time due to they close. ing oit of the pressure fluicljsupplyto ..valve.-.84j.-. Engagement of band 52 and drum 5|a locks planet 52 about drum .5 I a.

carrier ,5! against rotationand as the throttle control;member 85 i subsequently depressed,.,

drive ;is' transmitted from the converter. turbine member I 5; through shaft member 1 6, to annular member133; Rotation ofj.member 33 forwardly rotatably drives the sun gear portion .33a ,of. the. reversev planetary unit 31in a forward direction and this rotates planet opinions/v53 in ,a reversedirection.:. Rotationof planet pinions 53' in a re.-. verse direction on fixed'planet carrier .5 I.. causes a reverse drive'to be transmitted to. the annulus drum member 55; Drum member 55 is connected to the intermediate planet" carrier member 6 l Whichinturn is connected .to the rear planetary carrier "member" 'iE and the output'drum memv here-Mr Accordingly, reverse drivewill be transmitted-through this gear train when the reverse braking band f52-is locked about the .annulus drumi5 l a.

tain drive through this train it is;.merely. necess saryto move the drive control levertl; to the po-,- sition indicated as fLow andthis causes valv'e. 8 2- toadmit pressure fiuid to the rear planetary,

to ntional. form. nd? may behydrauIiCaHy p brake' band'cylinder'fl lsofas to lock brake band I.

'I2 about the drumportion?!lb ofjannulus gear; member 1|; As. the: throttlecontrolmemberiifi 1s subsequently-depressed to" increasethe engine speed; the intermediate 'shaftgtiil'; .Whichis di-v rectly connected to; the engine, rotatably drives the sun gear member'35 forwardly, Dueto an:

nulusgearfll beingheld bylband 12; the rotation of sun gear member vV35 forwardly causes forward rotation of planet pinion. gears 74 about thefixed annulus gear ll and this drives theplanet car- I riergl5 forwardly at a reduced speed ratio.. As.

planet'carrier member 75 is directly connected to the output shaft 45, throughdrum member 44, forward. driveisnow, transmitted through the. emergencyklow gearratio. It ,willbe noted that when, drive. is; being. transmitted through this,

Thisfemergency low gear. drive provides a positive lovrspeed drive particularly adaptedior use as a coasting brake dueltothefact that it i posirtivelygcomiected to theuengine, through mechanical-.r'neanseonly; Thispositive connection of the driven. shaft-$151110. the. driving. shaft ll] through a speed reduction sear, train .39Hprovides engine braking adaptedntowserve as ,a coasting brake. This;.positi.ve driveisalsoof. considerable benefit whenlit islnecessar-y tostart the vehicle by towing for ;the..rear .vvheels..of themvehicle, can be posi tively,connected..to.theensine crankshaft so as todrive theengine.duringtowing.

In; addition] to. en ine. braking, as-a means for increasing .,or..supplementing.the usual mecham ical braking. system, v this transmission provides meansjor. ohtainingseveral forms of turbo-brak-' ing. to further. assistor supplement the mechan ica1-:.-braking.and/or ,the' "engine braking devices. Itjwillbenoted thatvvhe'n operating in the emergency jlovv gear .driv'e,that.th engine crankshaft leis positively. onnected to output shaft 45, Ac cordingly the drive train Ior this. drive bypasses thetorqueconverter unitA and provides a means,

for.,,ob,taining= enginetbraking If turbo-braking is a so desired,whenoperating inthis gear ratio,v

itismerely necessary. to manually apply the brakingband 551,Zo. the low speed accelerating gear train. 38501: .the..,braking. band 52. of the reverse gear.traineflliandthiswilldrive the several component Wheellmembers of thetorque converter unit A at different relativespeeds and create a turbo-braking eifectlthatitends'to reduce the outputshaf-tspeed. It is obviousthat if the un- 'derdrive. braking bandu65'jis applied, whil operatinginthje emergency 10w gear drive or in direct driving then thenconverter impeller, l4 and the turbine, .l 5. will; be driven forwardly at different speeds.andthisjcreatesa turbo-braking effect. If almoreipovverfulturboebrake is desired than that producedjby -the..-app1ication of the underdrive brakeband thenthereverse braking band 52 maybefiappliedeand this Will. rotate the turbine member!!! or the converter unit A in a direction opposite' to, that of the enginefldriven impeller member I4.jandeconsequentlya .more powerful turboebrakin efiect.vvillbe. produced. Th manual meanslto apply the several braking bands, so asto.produce:turboebrakin r may be of any conmatically, electrically or. mechanically operated, While turborbraking. broadly is old in the art,

still th'e. particular. application herein disclosed, is thought to be novel that it remedies one of driven.- shaft, but. tosalsostall the driving engine.

With the transmission arrangement herein dis closed the turbo-brake is applied only when the driving and driven shafts are positively connected through a drive train that by-passes the converter unit. Accordingly, the turbo-brake produces a braking effect but it does not stall the engine for the driven wheels will drive the engine regardless of the reduction in speed of the converter impeller member I4 due to the reverse rotation of the converter turbine member I5.

The drive selector lever linkage 83 actuates the slidable rail member IOI which is adapted to operate the manual control valve 84. This rail member IOI also includes cam means I and I09 adapted to provide means to override the automatic control valves 89 and I59 and thus prevent undesired automatic shifts by the torque and speed responsive governor means 88. Rai1 member IOI carries a cam portion I08 adapted to be engaged by the follower end I04 of the springpressed valve stem I05 of control valve 89. Rail member IOI also carries a cam portion I09 adapted to be engaged by the follower end I50 of the spring-pressed valve stem I55 of control valve I59. As drive selector lever BI is moved to the various control positions the rail IOI is horizontally reciprocated and this causes vertical reciprocatory movement of the valve stems I05 and I55 so as to properly locate the control valve plungers I05 and I56 for the selected speed ratio drives. except fl-ligh, the control valve plungers I00 and I56 will be cammed downwardly by the rail member IOI so as to close the pressure fluid inlets to the valves 09 and I59. When valve plunger I06 is cammed downwardly to closed valve position this opens port 95 to drain the direct clutch cylinder 90 as well as the underside of the intermediate brake band cylinder 85. Likewise, in all but the High position of the selector lever Iii, the rail member IOI will cam valve stem I55 of control valve I59 downwardly and this will maintain valve I59 closed and drain the pressure fluid from lockup clutch cylinder I21. Obviously rail member IOI prevents the automatic upshifts to direct drive at all times except when the selector lever 6I has been moved to the High position. By reason of the cam mechanism I08 and I09 it is possible to set the selector lever BI in Start position and prevent the automatic upshift from the low speed, accelerating underdrive to the high speed underdrive when such would otherwise be accomplished by the governor means 80. When the drive selector lever 8I is placed in High position the cam portion I01 of the rail I 0| is positioned above the valve stem follower I04 and cam portion I09 is positioned above valve stem follower I54. This permits the valve plungers I06 and I56 to be automatically raised by springs III and IEI when the governor means 88 causes the de-energization of solenoids H0 and I60 to accomplish the automatic upshifts to direct drive. The starting, low speed, underdrive position of valve plungers I00 and I56 are indicated by the dashed lines in Fig. 3. On initial start the energized solenoid I60 holds the valve plunger I56 down to close off valve I59. When the output shaft speed and the torque demand are suitable for the upshift to the high speed underdrive then governor 89 die-energizes solenoid I60 and spring IBI raises plunger I55 to the open valve position. With the drive selector in the High position the rail cam portion I0! is positioned above follower I04, which permits the valve stem I05 to beraised to the open valve position by spring IIIif the solenoid H0 is deenergized. At low vehicle speeds the governor In all positions of the selector lever BI,

means 88, through the energized solenoid II 0, retracts the plunger I06 and holds it in the closed valve position where it blocks off the supply of pressure fluid to conduit 81. When vehicle speed and torque demand are such that the upshift to direct drive is in order, then governor means 03 causes a deenergization of the solenoid H0 and the compressed spring I I I then forces the plunger valve I06 upwardly to the open valve position so as to direct pressure fluid through the conduit 81 to the direct drive clutch C and the underside of the underdrive brake band cylinder 85.

The speed and torque responsive governor 00 is a double contact device that closes separate electrical circuits under different conditions of output shaft speed and torque demand. The shaft 99 of the governor 88 is intended to be connected to the output shaft 45 or to some output shaft driven member and the inlet connection I00 is adapted to connect a diaphragm walled chamber 887' within the governor to a torque responsive pressure unit such as the engine intake manifold or some similar mechanism. Mounted within the left end of governor 88 and drivingly connected to the driven shaft 99 is a rotatable speed responsive governor unit 05a having weights 88?) that are adapted to be actuated by centrifugal force. Actuation of weights 882) causes reciprocation of the shaft 880. Mounted on the left end of shaft. 88c is a diaphragm 88d that causes the torque responsive intake manifold pressure in the chamber 807' at the left end of the governor 88 to also cause reciprocation of the shaft 880. Shaft 880 carries a pair of switch contacts 08c and 80 respectively, which. are engageable with mating switch contacts 80g and 88h respectively so as to provide two separate electrical circuits through the governor control 80. The contacts 8871. and 88g are mounted on resilient spring strips for a purpose that will become readily apparent. The contacts 00 and 88h are spaced more closely than the contacts 88c and 88g. Overcenter compression springs are associated with each of the sets of electrical contacts to effect snap action thereof.

Operation of the governor control 08 is asfollows:

At closed throttle with the transmission set for the normal accelerating underdrive through gear train 38 the governor weights 80?) will not be rotating and the spring 88k of governor unit 88a will overcome the manifold vacuum in the chamber 887' at the right end of the governor 88 and urge the saft 880 towards the left so that both sets of electrical contacts will be closed. Because of the spring strip supports for contacts 889 and 88h it is possible to engage the more widely spaced contacts 886 and 88g after engagement of the more closely spaced contacts 86] and 88h. As vehicle speed increases and the torque load decreases conditions will be such as to permit the control 08 to cause a shift of the shaft 800 towards the right. After a predetermined amount of rightward shift of shaft 080, the more widely spaced contacts 80c and 88g will first be opened to causede-energization of solenoid I60 and opening of valve I59. to effect engagement of clutch D. This opening of valve I59 upshifts the transmission from the low speed fluid and mechanical torque multiplying underdrive into the positively connected, high speed underdrive. Subsequent shift of the shaft 080 towards the right an additional amount, due to increased output shaft speed and reduced torque load, will thereafter bring about an openingof the switch contacts 88, and "88h which will cause de-energization of. the; solenoid; lit, which :opens the valve 853 andeiiects engagement of 'clutohC' and disengagement-oi planetary brake bandits; The drive train rearrangement,;resulting from; this change upshiits theytransmissionfrom the high speed underdrive-to the positively connected direct drive.- ltisobviousythat other forms of controls could be used-to transmit thevarye ing speed and .torqueconditions, to the automatic control valves'and thusaccomplish the automatic shifts previously described in detail.

When. operating .in direct drive, with plunger valve liii; intheraisedaopen valve position, it is obvious that a depression of the foot throttle control member 436 to :its lower limit will-cause linkage 9! to move thevalvs member tilt to the closed valve position and thus overrule the governor control means 88; Valve plunger its may be moved to (closed valve position even though solenoid I Hi is .deenergized for .thelspringl iii is; merely compressed by the downward move ment of the valve plunger assembly iQ iEi S.

A governormeans H2 is provided to operate an electrically controlled by-pass valve 554 so as to automatically shift the transmission of drive from the emergency low gear. train 39 to the start ing, underdrive "gear train 33 when the vehicle speed drops below aminimum speed of approximately 2 or 3 miles per hour. This governor con trolled shift prevents stall of the engine at low vehicle speeds when the selector lever is positioned in the low gear emergency drive for the direct connection betweenthe engine and output shaft in emergency low gear is automatically replaced with, a drive through the underdrive gear train and the torquelconverter unit which permits slip between the-converter wheels when the ;vehicle is brought to rest Also, when the vehicle is to. be started through the emergency low gear train SEzthe governor means H2 initiates this start through the torque converter and the low speed underdrivevg-ear train 38 and then shifts the drive train to the low gear train 39 after the vehicle is' set in motion. This start through the converter unit prevents a jerky start and provides a fluid drive in all starting gear ratios. Furthermore, when the vehicle is being brought to a stop in theemergency low gear thegovernor means H2 insures that the transmission is automaticallyshifted into the starting underdrive gear ratio wherein the slip of the torque converter wheels,- at engine idling speeds, prevents creep of the vehicle.

The automatic shift from the emergency low gear drive into the starting-underdrive is eiiect ed in the following manner." With the drive selector lever 8i positioned for the emergency low gear drive, control valve 8t directs pressur fluid through conduit 18B, governor controlled valve its, and conduit 8i into the emergency low gear brake band cylinder 94. Pressure fluid in cylinder 96 applies the emergency low gear brake band 72 to the drum-oiannulus gear 'ii and this activates planetarygear train 39 for the transmission of the emergency low gear underdrive. In the event the vehicle speed drops down to approximately 2 or'3 miles per hour while the transmission is conditined for the emergency low gear 'underdrive, the governor means H2 will cause a clockwise rotation of the valve plug of valve unit Hit to a position that drains the cylinder 9t and directs pressure fluid from valve tithrough conduit ESE and valve i l into conduit Hi8 and into the lower portion of the cylinder of by-pass control valve J 713., Admissionof ,pressurefiuidinto, thelower portionof the cylinder in byepass con,-v

trol valve ll-ll forces the valve plunger l'ltlsee Figal), upwardly sov that the conduit i iilis closed on between the valve 86 and the underdrive brake, band cylinder 85.- Aiter; conduit it? has been 7 closed off by valv plunger l'iL-thepressure fluid in the lower portionyofv the cylinder of by-passcontrol valve no .-will then compress the valve spring H3 and raisethe plunger member I'M to such aposition that the inlet to conduit H1 is,

uncovered and this will permit-pressure fluid from the conduit I78 to pass through the by-pass control valve l'iiiand into the upper portionof underdrive brake band cylinder 85.; Admission-of; pressureiluid into-the upperportion of under drive cylinder 85 after valve-plungerv ill' has closed off the passage through conduit M2, causes; the application of brake band 65 to the drumof sun gear 64a and-this activates the underdriveto-valve ill] first raisethe by-pass control valve plunger Ill to close oii conduit M2, before, pressure fluid is admittedto the ,underdrive braking cylinder 35, so that the, pressure fiuiddrain from cylinder 85 will be closedoii" prior to the admis-- sion of pressure flu-id intogtheunderdrive brake band cylinder 85."

I claim;

1. In a hydrodynamic transmission, an input shaft and an output shaft, a hydraulic torque converter unit comprising an impeller member, a turbine member and areaction member, means drivingly connecting said impeller member to said input shaft, a variable speed gear. unit operably connected betweensaid shafts comprising a planetary gear train having meshingly engaged sun, pinion and. annulusgears, a carrier for said pinion gears, and braking means for said sun gear, said annulus gear being drivingly connected to said turbinev member and said pinion gear carrier being drivingly connected to said output shaft to provide means for the transmission of a. low speed, combination hydraulic and mechanical torque multiplying,underdrive,a first clutch means adapted to directly connect said impeller and turbine members to lock said torque converter unit out of said low speed underdrive train to thereby provide means for the transmission of a positive, high speed underdrive, a second clutch means adapted to directly connect said input and output shafts for the transmission of direct drive, output shaft speed and torque responsive control means adapted to operate said clutch means to automatically upshift said low speed underdrive to said high speed underdrive and to said direct drive and to automatically downshiit said directdrive back into said high speed underdrive and said low speed underdrive, and manually controlled meansadapted to operate said second clutch means to overrule said speed and torque responsive means to provide means for-accomplishing a kiCiiCiOWll from said direct drive to said high speed underdrive.

2. In a hydrodynamic transmission, ail-input said input shaft, a variable speed gear unit operably connected between said shafts comprisingand turbine members to lock said converter unit out of said combination hydraulic and mechani cal underdrive train to thereby provide a completely mechanical underdrive train, a second clutch means adapted to directly connect said in- ,put and output shafts for the transmission of direct drive, control means adapted to operate saidclutch means to automaticallyupshift said combination hydraulic and mechanical underdrive to said completely mechanical underdrive and to said direct drive and to automatically downshift said direct drive to said completely mechanical underdrive and to said combination hydraulic and mechanical underdrive, manually actuated means adapted to operate said second clutch means to provide means for accomplishing a kickdown from said direct drive to said completely mechanical underdrive anda second planetary gear train adapted to be positively connected between said input and output shafts to provide means for the transmission of an emergency low gear underdrive said second gear train having its sun gear driven by the input shaft, its pinion carrier for its pinion gears drivingly connected to the output shaft and its annulus gear associated with a braking means.

3. In a power transmission, an input shaft, an output shaft, a hydraulic torque converter unit, comprising impeller and turbine members, and

' a variable speed gear unit operatively connected in series between said shafts, said gear unit comprising a gear reduction means adapted to be driven by the turbine member of said converter unit to provide means for the transmission of a combination hydraulic and mechanical torque multiplying, low speed, underdrive from said input to said output shaft, a first clutch means adapted to directly connect the converter impeller and turbine members to lock said torque converter unit out of said low speed underdrive train and provide means for the transmission of a high speed mechanical underdrive between said shafts, a second clutch means adapted to directly connect said shafts to provide means for the transmission of direct drive between said shafts,

18 prising a first gear reduction means adapted to be driven by the turbine member'of said converter unit to provide means for, the transmission of a combination hydraulic and mechanical torque multiplying, low speed, underdrive from said in put to said output shaft, a first clutch means adapted to directly connect theconverter impeller and turbine members to lock said torque converter unit out of said low speed underdrive train and provide means for the transmission of a high speed mechanicalunderdrive, between said shafts, a second clutch means adapted to directly connect said shafts to provide means for the transmission of direct drive between said shafts,

output shaft speed'and torque responsive control providing means to overrule said automatic control means to accomplish a kickdown from said direct drive to said high speed underdrive which drive is transmitted by means positively connecting'said input shaft to said output shaft through said gear means, and a second gear reduction means adapted to be positively connected between said shafts so as to provide means for the transmission of, an emergency low gear under output shaft speed and torque controlled means tooperate said first and second clutch means to provide for the automatic upshifting of'said low speedunderdrive to said high speed underdrive and to said direct drive and to provide for the automaticdownshifting of said direct drive to said high speed underdrive and said low speed underdrive, and manually actuated means adapted to operate said second clutch means and to provide means to overrule said speed and torque controlled means for accomplishing a kickdown from said direct drive to said high speed underdrive which drive is transmitted by means positively connecting said input shaft to said output shaft through said gear means.

4. In a power transmission, an input shaft, an output shaft, a hydraulic torque converter unit, comprising impeller and turbine members, and a variable speed gear unit operatively connected in seriesbetween said shafts, said gear unit comdrive particularly adapted for use as a coasting brake.

5. In a power transmission, an input shaft, an output shaft, a hydraulic torque converter unit, comprising impeller and turbine members, and a variable speed gear unit operatively connected in series between said shafts, said gear unit comprising planetar gear means having meshingly engaged sun, pinion and annulus gears, a carrier for said pinion gears, and braking means for said sun gear, said annulus gear being arranged to be driven by the turbine member of said converter unit so as toprovide means for the transmission of a combination hydraulic and me-' clutch means adapted to be engaged to directly connect said input shaft to the annulus gear of said planetary gear means so as to provide means for the transmission of a high speed, mechanical, underdrive between said shafts, a second clutch means carried by said shafts adapted to be engaged for the transmission of direct drive between said shafts, speed and torque responsive control means to operate each of the clutches to provide for an automatic upshift from said low speed underdrive to said high speed underdrive and tosaid direct drive and 'to provide for an automatic downshift from said direct drive to said high speed underdrive and said low speed underdrive, and manually controlled means to operate the second clutch to effect a kickdown from said direct drive to said high speed, mechanical underdrive, said kickdown being effected by disengagement of said second clutch, engagement of said first clutch, and activationof said planetary gearmean-s;

action members adapted to be driven by said input shaft, a variable speed gear unit comprising a first planetary gear train adapted to be drive ingly connected between said shafts to provide means for the transmission of a positive, emergency low speed underdrive, a second planetary gear train adapted to be drivingly connected between said turbine wheel and said output shaft to provide mean for the transmission of a combination hydraulic and mechanical, high torque multiplying, low speed underdrive, a first clutch means adapted to connect said turbine member and said input shaft, a second clutch means carried by said shafts adapted to connect said shafts to provide means for the transmission of direct drive, control means adapted to auto-' matically activate said first clutch means to connect said impeller and-turbine members and convert said hydraulically transmitted low speed underdrive into a high speed mechanical underdrive, control means adapted to automatically activate said second clutch means to convert said high speed mechanical underdrive into direct drive, and control means adapted to effect automatic downshifting from said direct drive to said high speed mechanical, underdrive and to said low speed underdrive.

7, In a hydrodynamic transmission, an input shaft, an output shaft, a hydraulic torque converter unit comprising impeller, turbine and reaction me mbers adapted to be driven by said inputshaft, a variable speed gear unit comprising a first planetary gear train adapted to be drivingly connected between said shafts to provide means for the transmission of a positive, emer gency low speed underdrive, a second planetary gear train adapted to be drivingly connected between said turbine wheel and said output shaft to provide means for the transmission of a combination hydraulic and mechanical torque multiplying underdrive, a first clutch means adapted to be activated to engage the impeller and turbine members of said converter unit to convert said combination hydraulic and mechanical underdrive into a completely mechanical underdrive adapted for high speed acceleration, a second clutch means carried by said shafts adapted to activated t o connectv said shafts for. the transmission of direct drive, control means adapted-to automatically activate said first clutch means at a first predetermined output shaft speed and torque condition, and to subsequently activate said secondclutch at a second predetermined output shaft speed and torque condition, and a third planetary gear train adapted to be drivingly connected between said turbine member and said output shaft to provide means for the transmission of a reverse drive.

8,; In a hydrodynamic transmission, an input shaft, an output shaft, a torque converter unit comprising impeller, turbine and reaction Wheels adapted to be driven by said input shaft, a variable speed gear unit comprising a planetary gear train adapted to be drivingly connected between said turbine wheel and said output shaft to provide means for the transmission of a combination fluid and mechanical, torque multiplying, low speed underdrive therebetween, a first clutch means carried by said shafts adapted to be engaged therebetween for the transmission of direct drive, governor controlled means adapted to operate said first clutch to effect an automatic upshift from said low speed underdrive to said direct drive and to effect an automatic downshift from said direct drive to said low speed underconverter unit and adapted to be engaged to ascends 2c directly connect the impeller andturb i ne wheels of said converter unit so as to provide means to transmit a positive drive from said input shaft to said planetary gear train, and manually co n trolled means to operatesaid first clutch adapted to provide means to'effect a kickdown from said direct drive to' a positive, mechanical high speed, underdrive transmitted through said second clutch and said planetary gear train.

9. In a power transmission, an input shaft,'-'a fluid tor ue converter unit comprising impeller and turbine members drivingly connected to said input shaft, a second shaft connected -to and adapted to be driven by the turbine member" of said converter unit, first and second planetary gear trains connected to and adapted to be selectively driven by said second shaft, a third planetary gear train'positively connected to said input shaft, an output shaft, means adapted to drivingly connect each of said planetary gear trains to said output shaft, means adapted to activate said first gear train so as to transmit a combination fiuid and mechanical, low speed underdrive from said input to said output shaft, means adapted to activate said second gear train so as to transmit a reverse drive from said input to said output shaft, means adapted to activate said third gear train so as to transmit a positive, emergency low gear drive to said output shaft, said third gear train being adapted to serve as a coast braking drive train, a first clutch means carried by and adapted to be engaged to connect said input and ontput shafts for the transmission of a direct drive, governor controlled means adapted to operate said first" clutch to efiect an automatic upshiftgfrom said low speed underdrive to said direct drive and to effect an automatic downshift from said direct drive to said low speed underdrive, a second clutch means carried by and adapted to-be engaged to directly connect said input shaft to said first planetary gear train to provide means'for the transmission of a positive, high speed underdrive, and manually controlled means adapted to disengage said first clutch to effectalrickdown from said direct drive to said po sitive,- high speed underdrive transmitted through said. second clutch means and ,said first planetary gear "train.

10. In a power transmission, an input shaft, a I

hydraulic torque converter unit comprising impeller and turbine members drivingly connectedto said input shaft, a secondshaft connected to and adapted to be driven by the turbine member of said converter unit, a firstplanetary gear train connected to and adapted to be driven by said second shaft, a second planetary gear train positively connected to saidinput'shaft, an output shaft, means adapted to'drivingly connect-said planetary gear trains to said output shaft, means adapted toactivate said first gear train so as to transmit a combination hydraulic and mechanical, torque multiplying underdrive from said input to said output shaft, a first clutch means associated with said converter members and adapted to be-activated to directly connect the impeller member of said converter unit to said first gear train to convert said-torque multiplying undera drive to a completelymechanicalunderdrive, means adapted to activate said second gear train so as to transmit a positive, emergency low-gear drive from said input to said output shaft, a second clutch means mounted between said input and output shafts and adapted tobeactivated toconnect said input and output shafts for t he transmission of a direct drive, speed and torque ical underdrive and to said combination fluid and mechanical underdrive. V

11. In a power transmission, aninput shaft, an output shaft, a hydraulic torque converterunit comprising operatively associated impeller, ture' bine and reaction wheels, means providing a d'riving connection between said input shaft and said impeller wheel, a planetary gear train comprising an annulus gear, a sun gear and aplanet carrier mounting planet gears interposed between said converter unit and said output shaft, means drivingly connectingsaid turbine wheel to said annulus gear, drive transmitting means connecting said planet carrier to saidoutput shaft, braking means adapted to anchor said sun gear against rotation so as to activate said gear train and provide means for the transmission of a combination hydraulic and mechanical, high torque multiplying, underdrive to said outputshaft, a first clutch means adapted to connect said input and output shafts for the transmission of a positive direct drive, and a secondplutch means adapted to drivingly connect said input shaft to the annulus gear of said planetary gear train so as to lock said converter unit out of the combination hydraulic and mechanical underdrive train and provide means for the transmission of a positive, completely mechanical underdrive to said output shaft. 1

12. In a power transmission, an inputshaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means providing a driving connection between said inputshaft andsaid impeller wheel, a planetary gear train comprising an annulus gear, a sungear and a planet carrier'mounting planet gears interposed between said converter unit and said output shaft, means drivingly connecting said turbine wheel to said annulus gear, drive transmitting means connecting said planet carrier to said output shaft, braking means adapted to anchor said sun gear against rotation so as to activate said gear train and provide means for the transmission of a combination hydraulic and mechanical, high torque multiplying, underdrive to'said output shaft, a first clutch meansadapted to connect said input and outputshafts for the transmission of a positive direct drive, and a second clutch means adapted to drivingly connect said input shaft to the annulus gear of said planetary gear train so asto lock said converter unit out of the combination hydraulic and mechanical underdrive train and provide means for the transmission of a positive, completely mechanical underdrive to said output shaft and control means adapted to effect automatic upshiftingfrom said combination hydraulic and mechanical underdrive to said completely mechanical underdrive and to said direct drive, and to automatically downshift said direct drive to said completely mechanical underdrive and to said combination hydraulic and mechanical underdrive.

13. In a power transmission, an input shaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, tur-i bine and reaction wheels, means providing a driving connection between said input shaft and said impeller wheel, a planetary gear train comprising an annulus gear, a sun gear and aplanet carrier mounting planet gears interposed between said converter unit and said output shaft, means drivingly connecting said turbine wheel to said annulus gear, drive transmitting means connectingsaid planet carrierto said output shaft, braking means adapted to anchor, said sun gear against rotation soas ,to activatemsaid gear train and provide means for thetransmission of a combination hydraulic and mechanical, high torque mul-c tiplying,-underdrive to saido-utput shaft, afirst clutch means adapted :toconnect said input and output shafts vfor the transmission of a positive direct drive, and a second clutch means adapted to drivingly connect said input shaft to the annu-, lus gear of said planetary gear train so fasto lock said, converter unit out of the combination hydraulic and mechanical underdrive train and provide means for the. transmission of a positive, completely mechanicalunderdrive to saidl output shaft and control means adapted-to effect auto:

matic upshifting from said combinationhydraulic and mechanical underdrive ,to; said completely mechanical underdrive and to said direct drive, and to automatically downshift said direct drive to said completely. mechanical underdriveand to saidcombination hydraulic and .mechani-, cal underdrive, and manually actuated. means adapted to kickdown said direct drive to said completely mechanical underdrive.

1a. In a power transmission, an input shaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means providing a driving connection between said input shaft and said impeller wheelyfirst and second planetary gear trains :interposedbetween said-converter unitand said output shaft, drive transmitting means connecting said turbine wheel to the annu-w lus gear of saidfirst planetar gear train and to the sun gear of saidsecond planetary gear train, drive transmitting means connecting the planet carrier of said first planetary gear train and the annulus gear of said second planetary gear train to said outputshaft; braking means adapted to anchor the sun gear of said first planetary gear train against rotation so as to provide means for transmitting a combination hydraulic and mechanical, low speed underdrive to said output shaft, braking means adapted'to anchor the planet carrier of said second planetary gear train against rotationso as to provide means for transmitting a reverse drive to said output shaft, a first clutch means adapted to connect said input and output shafts for the transmission of direct drive, a second clutch means adapted to drivingly connect said input shaft to the annulus gear of said first planetary gear train so as gear trains interposed between said converter unit and said output shaft, drive transmitting means connecting said turbine wheel to the annulus gear of said first planetary gear train and to the sun gear of said second planetary gear train, drive transmitting means connecting the aiecepzoe 23' planet carrier 'of'said first planetary geartrain and the annulu gear of said second planetary gear train to said output shaft, braking means aditptedto anchor the "sun gear 'of 'said first planetary gear' train against rotationso as to provide means for transmitting a combination hydraulic and mechanical, low speed underdrive to' s'a-id output shaft, braking means adaptedto anchor the planet carrier of said second planetary gear traina'gain'st rotation so as top'rovide means" for transmitting a reverse :drive to said output shaft, a first clutch means'adapted :to connect said input and output shafts for the transmission of direct drive, a second clutch means adapted to drivingly connect said input shaft to the annulus gear of *said'first planetary gear train so as to lock said converter unit out of sai'd' low speed underdriv'e train and provide meansfor the transmission of a completely mechanical, high speed, underdrive tosaid output shaft, control means adapted to effect'automatic upshi-fting'from saidlow speed underdrive tov said high speed 'underdrive to said direct :drive and automatic downshifting from said direct drive to 'said high speed underdrive to said lo'wspeed underd-rive.

1'6.In a power transmission, an input shaft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means providing a driving connection b'etweenisaid input shaft and saidimpellenwheel, first and second planetary gear trains interposed between said converter unit :and said'outputshaft, drive transmitting means connecting said turbine wheel to the annuluszgear of said first-planetary gear train and to the sun gear of saidsecond planetary gear train, "drive transmitting means connecting the planet carrier of said first planetary gear train and the annulus gear of said second planetary gear train to said output shaft, braking means adapted to anchor the sun gear of said first planetary gear train against rotation :so as to provide means for transmitting a combination hydraulic and mechanicaLloW speed underdrive tos'aid output shaft,"braking means adaptedzto anchor the planet carrier of saidisecondplanetary -gear train'againstsrotation so ':as to'provide means-for transmittinga reverse :drive to said outputshaft, a first clutch means adapted to connect said input and output. shafts for the transmission of direct drive, .a .second clutch means adapted to drivingly .connect said input shaftto the annulus gear of said firstxplanetary gear train so-as to lock said converter unitout of said low speed underdrive train and provide means for the transmission of a completely mechanicaL high speed, underdrive tosaid output shaft, control means adapted to effect automatic upshifting from said low speed 'underdrive to said high speed underdri-ve to said direct drive and automatic downshifting fromvsaid direct drive'to said high speed underdrive to said low speed underdrive, and. manually :actuated .means adapted to kickdown said. direct-:drive to said positive high speed underdrive.- 3 r Y 1'7.' In"a power transmission an inputvsh'aft, an output shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, :mean's providing is driving connection between'said input shaft and said impeller wheel, first and secondplanetary gear trains interposed between said converter unit and said output shaft, drive transmitting means connecting said turbine wheel-to theannulusigear of. said first planetary gear :train; means. drivingly connecting :said Linput shaft to thesunrgear. of said secondpplanetarygeartrain, means connecting the: planet. carriers [of said first and secondcplanetaryn'gear 1312111181130 said output: shaft, .braking means adapted to :anchor the sun ,::gear of 'said first planetary gear train against-rotation so as to provide means for.trans:- mitting a combination hydraulic and mechanical ,ctorque multiplying 'underdrive to said-output shaft, braking means adapted: to anchortheta!!- nulus ggEl-I. of. said isecond, planetary gear ,train against, rotation :so "as, to-provide means :for transmitting a positive; completelyimechanical low' :gear :underdrive toysaid output ,shaft;:;a'.:first clutchzmeansadapted toconnect said input and outputshafts for. the transmission of .directdriva: a second clutch means adapted to drivingly;connect said inputshaft tothe annulus'gearof-said first planetary gear trainlso ,as to .providea drive train for the transmission ,of'a second positive, 7

completelymechanical,-underdrive'. v

18. Ina power transmission, an input :shaft, an output shaft, a hydraulictorque converter unit comprising operatiyely associated impeller, turbine ;and reaction wheel's;,means providing-a driving connection between said; input shaft and said impeller 'wheel,-first,second and third planetary gear :trains interposed between said con! verter unit and said output shaft, means connecting said turbine wheel to ,theannulusgear of said first planetary gear, train endutoc the sun gear of said second planetaryygea-r 'train means connecting said input shaft to. "the sun-sear :of said third planetary- ,gear; train,...m,eans ,connecting the planet carriers of said-first1and third planetary gear trainsrand the annulus :EGQJIQOf said second planetary gear train {to said output shaft, braking meansadaptedito anchor theisun gear-of saidfirst planetary, geartrain againstrotation so 'as'jto provide means for transmitting a $10)? :speed underdrive -to said;coutput.: shaft; braking meanszadapted; to anchor the-;planet-carrier of said second planetarygear atraimag i rotationr'so :as to provide means for-transmitting aireverse; drive to; said output shaft, braking means "adapted to anchor. .the ;:annulus ,gejarof said third ,qplanetary igear traimagainst; rotation so:as to providemeans for transmitting a positive, j low -:gear ratio. -underdrive: to said :output shaft, ;-a first clutch means adapted to connect said input and output shaftsfor,thertransmis sion' of direct drive, a secondclutchymean-s adapted .to drivingly connect said input shaft-t0 the annuluslgear ;of said first :planetary gear train so as to provideadrive train for. the transmission of aposi-tive, high speed,,underdrive,

.1-9. In a .p-ovver transmission-an input; shaft, an output shaft, -;a hydraulic torque converter unit comprising impeller, turbine and reaction wheels opera tiveiy associated for ,the transmission of torque, means providing-g et drive transmitting connection betweenlsaid input shaft and saidimpeller wheel,- api anetary geartrain, com, prising operatively associatedsun, annulus and planet gears and axplanetgear carrier interposed between said converter unit and said outputshaft and adapted to .be driv-ingly connected therebetween, driving transmitting imeans connecting said turbine wheel .to the annulus gear of said planetary gear train, drive transmitting means connecting the planet gear carrier of said planetarygear train to said output shaft, braking means adapted to lock thesungear of said planetary gear-train against rotation so as to activate said gear train and provide drive transmitting means particularly adapted for transmitting a low speed, high torque multiplication underdrive to said output shaft, a first clutch means mounted between said input and output shafts and adapted to be engaged to connect saidshafts soas to provide means for the transmission of direct drive between said shafts, a second clutch means associated with said converter unit and adapted to be engaged to directly connect said converter impeller and turbine wheels so as to provide an input to said gear train that by-passes the converter unitand directly connectssaid inpu-t shaft to the annulus gear of said planetary gear train to thereby provide a drive train particularly adapted for transmitting a positive high speed underdrive to said output shaft.

'20. In a hydrodynamic trans-mission, a driving shaft, a driven shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction members interposed between said shafts, drive transmitting means connecting said driving shaft and said impeller member, lanetary gear means interposed between andadapted to be drivingly connected to said shafts comprising a first planetary gear train mounted on said driving shaft and adaptedto be drivingly connected between said turbine member and said driven shaft to provide means for the transmission of a combination hydraulic and mechanical, torque multiplying underdrive to said driven shaft, a second planetary gear train mounted on said driving shaft and adapted to be drivingly connected between said turbine member and said driven shaft to provide means for the transmission of a reverse drive to said driven shaft, a third planetary gear train mounted on said driving shaft and adapted to be drivingly connected between said driving and driven shafts to provide-means for the transmission of a positive, low gear ratio underdrive to said driven shaft, clutch means carried by said shafts a-d aptedto be engaged to provide means for the transmission of a positive direct drive between said shafts, and braking means to selectively activatesaid gear trains, said braking means'being arranged to be selectively applied to either of said firstor second planetary gear train during the transmission of said positive underdrive through said third gear train whereby the relative rotative speeds of said converter turbine and impeller members are varied so as to provide a turbo brake to said positive underdrive.

21. In a hydrodynamic transmission, a driving shaft, a driven shaft, a hydraulic'torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means drivably connecting said driving shaft to said impeller wheel, planetary gear means interposed between and adapted to be activated to drivingly connect said shafts comprising a first planetary gear train mountedon said driving shaft and adapted to be drivingly connected between said turbine member and said output shaft to provide means for the transmission of a converter transmitted, torque multiplying underdrive to said driven shaft, a second planetary gear train mounted on said driving shaft and adapted to be drivingly connected between said shafts to provide means for the transmission of a positive, low gear ratio underdrive to said driven shaft, and braking means to selectively activate said gear trains, said braking means beingsa-d'apted to be applied to said first gear train, whensaid pos itive, low gear ratio underdrive is being transmitted by said second gear train, to activate said first gear train and vary the relative rotative speeds of said converter turbine and impeller members so as to provide a turbo-braking means for said positive underdrive.

22. In a hydrodynamic transmission, a driving shaft, a driven shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means driv- Jably connecting said driving shaft to said impeller wheel, planetary gear means interposed between and adapted to be drivingly connected to said shafts comprising a first planetary gear train mounted on said driving shaft and adapted to be di'l'vingly connected between said. tllrbih'e member and said output shaft to provide means for the transmission of a reverse drive to said driven shame second planetar gear t'r-ain mounted on said driving shaft and adapted to be drivingly connected between said shafts to pmvi-de means for the "transmission of a positive, low gear ratio, forward underdrive to said driven shaft, and braking means to selectively activate said gear trains, said braking means being adapt= ed to be applied to said first planetary gear train, when said positive underdriveis being trans mitted by said second gear train, to activate said first planetary gear train and vary the rotative speed of said turbine member with respect to the speed of said impeller member so as to provide a turbo-braking means for said positive tinder drive.

23. A planetary type transmission mechanism adapted to be selectively driven by the driving and driven members of a hydraulictorque trans mitting unit comprising a first shaft connected to the said driven member, a second shaft, concentrically arranged with respect to said first shaft, connected to the said driving member, and an output shaft, a first, a second and a third planetary gear train interposed between said first and second shafts and said output shaft, said gear trains each comprising meshingly engaged sun, annulus and planet pinion gears vandeach including a carrier for rotatably supporting the pinion gears thereof, said first shaft mounting the sun gear of the first planetary gear train and the annulus gear of the second planetary train, said second shaft mounting the sun gear of the third planetary gear train, means drivingly connecting the annulus gear of said first planetary gear train to said output shaft, means drivingly connecting the planet carriers of said second and third planetary gear trains to said output shaft, brake means adapted to be applied to the planet carrier of said first planetary gear train to activate said first train and provide means for transmitting a reverse drive from said first shaft to said output shaft, brake means adapted to be applied to the sun gear of said second planetary gear train to activate said second train and provide means for transmittinga first forward, low speed, under-drive from said second shaft to said output shaft, brake means adapted to be applied to the annulus gear of said third planetary gear train to activate said third train and provide means for transmitting a second, forward, low speed, underdrive from said second shaft to said outputshaft; and clutch means'ad-ap'ted to drivingly connect said second shaft and said output shaft to provide means for the transmission of a positive direct drive therebetween.

24. A planetary type transmission mechanism adapted to be selectively driven by the drivin and driven members of a hydraulic torque transmitting unitcomprising a firstshaft connected to the said driven member, a second shaft connectedto the said driving member, and an output shaft, a first, a second and a third planetary gear train interposed between said first and sec-- ond shafts and said output shaft, said gear trains each comprising meshingly engaged sun, annulus and planet piniongearsandincluding a carrier for-rotatably supporting the pinion gears, said first .shaft mounting the sun gear of the first planetary gear train and the annulus gear of the secondplanetary train, said second shaft mounting the sun gear of the third planetary gear train, :means drivingly connecting the annulus gear of said first planetary gear train to said output shaft, meansdrivingly connecting the planetcarriers of said second and third planetary gear trains to saidoutput shaft, brake means adapted tobe applied to the planetcarrier of said first planetary gear train to activate said first train and provide means for transmitting a reverse drive from said first shaft to said output shaft, brake means adapted to be applied to the sun gear of said second planetary gear train to activate said second train and provide means for transmitting a forward low speed underdrive from said first shaft to said output shaft, brake means adapted to be applied to the annulus gear of said third planetary gear train to activate said third train and provide means for transmitting a forward underdrive from said second shaft to said output shaft, clutch means adapted to drivingly connect said second shaft and said output shaft to provide means for the transmission of direct drive therebetween, and clutch means adapted 'to be connected between said second shaft and the annulusgear of the second planetary gear train toprovide meansfor the transmission of a positive, forward, high speed under drive between said second shaft and, said output shaft,

2,5. A planetary type transmission mechanism adapted to ,be selectively driven by the driving and driven members of a hydraulic torque transmitting unit comprising first shaft connected to the said driven member, a second shaft connected to the said driving member, andan output shaft, a-firstand second planetary gear train interposed between said first and second shafts and said output shaft, said gear trains each comprising .meshingly engaged sun, annulus and planet pinion gears and including a carrier for rotatably supporting the pinion gears, said first shaft mounting the sun gearof the first planetary gear train and the annulus gear of the second planetary train, means drivingly connecting the annulus gear of said first planetary gear train to said output I shaft, means drivingly connecting the planet carrier of said second gear train to said output shaft, brake means adapted to be applied-to the planet carrier of said first planetary gear train to activate said first train and provide means for transmitting a reverse drive from said first shaft to said output shaft, brake means adapted to be applied to the sun gear of said seconed planetary gear train to activate said second train and provide means for transmitting a .forward low speed underdrive; from said-first shaft to .said output shaft, clutch means adapted to drivingly connect said second shaft and said output shaft to provide means for the transmission of direct drive therebetween, and clutch means adapted to be connected between said second shaftand, theannulus gea Qft second p n ary ar train, to provide means :forithe transgear train interposed between said first :andsecondshafts and said output shaft,;said gear trains each comprising meshingly engaged sun, annulus and planet'pinion gears and including a carrier for rotatably supporting the pinion gears, said first shaft mounting the sun gear of thQgfiISt planetary gear train and the annulus gear of the second planetary train, said second shaft mounting the ,sungear of the third pl-anetary gear train, means drivingly connecting the annulus gear of said first planetary gear train to said output shaft, means drivingl-y connecting the planet carriers of said second and third planetary gear trains to-said output shaft, brake means adapted to be applied to the planet carrierpf said first planetary gear train to activatesaid first train and provide means for transmitting a reverse drive from said first shaft to said'output shaft, brake means adapted to be applied tothe sun gear of said second planetary gear train to activate said second train and provide means for transmitting a forward low speed underdri vefrom said first shaft to said output shaft, brake-means adapted to beapplied to the annulusgear ofsaid third, planetary gear train to activate said third train and provide means for transmitting a for-- ward underdrive from said second shaft to said output shaftclutch means adapted todrivingly connect said second shaft and said output shaft toprovide means for the transmission of direct drive. therebetween, and clutch meansladapted to be connected between said second shaft and the annulus gear of the second planetary gears-train to provide means for the transmission of a positive, forward, high speed .underdrive betwensaid second shaft and said output shaft, speed and torque responsive means to independently operate the several. clutch means and speedresponsi've meansto -effect automatic operation ofthe brake means for the second and third gear trains to provide a means for converting the positive underdrive into the low speed underdrive when the output .shaft speed is reduced to a predetermined value. i 5

.27. In a hydrodynamic transmission, a driving shaft, a driven shaft, a hydraulic torque .converter unit comprising operatively (associated vi-mpeller, turbine and reaction members interposed between said shafts, drive transmitting means connecting said driving shaft and said impeller member, planetary gear means interposed between and adapted to be drivtngl-y connected to said shafts comprisinga first planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected between said turbine member and said driven shaft to provide means for the transmission of a icomb-inationhydraulic and mechanical, torque multiplying underdrive to said driven shaft, a second planetary ,gear train mounted-on said drivingshaft having certain elements thereof arranged to be driving-1y connected between said turbine member and said driven shaft to provide means for thetransmission of a reverse 29 drive to said driven shaft, a third planetary gear trainmo'untedon said driving shaft having certain elements thereof arranged to be drivingly connected between said driving and driven shafts toprovide means for the transmission of a positive, 10w gear ratio, underdrive to said driven shaft, clutch means carried by said shafts adapted to be engaged to provide means for the trans mission of a positive direct drive between said shafts, and braking means to selectively activate said gear trains, said braking means being arranged and adapted to be applied to other elements of said first planetary gear train during the engagement of said clutch means and the transmission of the positive direct drive, whereby the relative rotative speeds of said converter turbine and impeller members can be varied so as to provide a turbo braking action on said positive direct drive. i V

28. In a hydrodynamictransmission, a driving shaft, a driven shaft, a hydraulic torque converter unit comprising operatively associated imp'eller, turbine and reaction members interposed between said shafts, drive transmitting means connecting said driving shaft and said impeller member, planetary gear means interposed between and adapted to be drivingly connected to said shafts comprising a first planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connectedbetween said turbine member and said driving shaft'to provide means for the transmission of a combination hydraulic and mechanical, torque multiplying underdrive to said driven shaft, a second planetary gear train mounted on said driven shaft having certain elements thereof arranged to be drivingly connected between said turbine member and said driven shaft to provide means for the transmission of a reverse drive to said driven shaft, a third planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected between said drivingand driven shafts to provide means for the transmission of a positive, low gear ratio, underdrive to said driven shaft, clutch means carried by said shafts adapted to be engaged to provide means for the transmission of a positive direct drive between said shafts, and braking means to selectively activate said gear trains, said braking means being arranged and adapted to be applied to other elements of said second planetary gear train during the engagement of said clutch means and the transmission of the positive direct drive, whereby the relative rotative speeds of said converter turbine and impeller members can be varied so as to provide a turbo braking action on said positive direct drive.

29. In a hydrodynamic transmission, a driving shaft, a driven shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction members interposed between said shafts, drive transmitting means connecting said driving shaft and said impeller member, planetary gear means interposed between and adapted to be drivingly connected to said shafts comprising a first planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected between said turbine member and said driven shaft to provide means for the transmission of a combination hydraulic and mechanical, torque multiplying underdrive to said driven shaft, a second planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected between said turbine member and said driven shaft to provide means for the transmission of a reverse drive to said driven s'haftya third planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected between said driving and driven shafts to provide means for the transmission of a positive, low gear ratio, underdrive to said driven shaft, and braking means to selectively activate said geartrains, said braking means being arranged and adapted to be selectively applied to other elements of said first planetary gear train during thetransmission of said positive underdrive through said third gear train whereby the relative rotative speeds of said converter turbine andimpeller members can be varied so as to provide a turbobrake to said positive underdrive. i

30. 'In'a hydrodynamic transmission; a driving shaft, a driven shaft, a hydraulic torque converter unit comprising operatively associated inipeller, turbine and reaction members interposed between said shafts, drive transmitting means connecting said driving shaft and said impeller member, planetary gear means interposed between and adapted to be drivingly connected to said shafts comprising a first planetary gear train mounted onsaid driving shaft having oertain elements thereof arranged to be drivingly connected between said turbine memberand said driven shaft to provide means for, thetransmission of a combination hydraulic andmechanical, torque multiplying underdrive to said driven shaft, a second planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected be-- tween said turbine member and said driven shaft toprovide means for the transmission of areversedrive to said drivenshaft, a third planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected'between said driving and driven shafts to provide means for the transmission of a positive, low gear ratio, underdrive to said driven shaft, and braking means to selectively activate said gear trains, said braking means being arranged and adapted to be selectively applied to other elements of said second planetary gear train during the transmission of ,said positive underdrive through said third gear train whereby the relative rotative speeds of said converter turbine and impeller members can be varied so as to provide a turbo-brake to said positive underdrive.

31. In a hydrodynamic transmission, a driving shaft, a driven shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means drivably connecting said driving shaft to said impeller wheel, planetary gear means interposed between and adapted to be activated to drivingly connect said shafts comprising a first planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected between said turbine member and said output shaft to provide means for the transmission of a converter transmitted, torque multiplying, underdrive to said driven shaft, a second planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected between said shafts to provide means for the transmission of a positive, low gear ratio, underdrive to said driven shaft, and braking means selectively applicable t other elements thereof the several gear trains to -activate-- the individual gear trains for the transmission of drive between said shafts, a drive ratioselector means, and-output shaft speed responsive means to control the activation and deactivation. of the several gear trains, irrespective of the drive ratio selector means. r

I 32.111 a hydrodynamic transmission, a driving-shaft, a driven shaft, a hydraulic torque converter unit comprising operatively associated impeller, turbine and reaction wheels, means drivably connecting said driving shaft to said impeller wheel, planetary gear means interposed between and adapted to'be activated to drivingly connect said shafts comprising a first planetary I gear train mounted' on said driving shaft having certain ,elements thereof arranged to be drivingly connected between said turbine member and said output shaft to provide means for the transmission of a converter transmitted, torque multiplying, underdrive to said driven shaft, a second planetary gear train mounted on said driving shaft having certain elements thereof arranged to be drivingly connected between said shafts to providemeans for the transmission of a positive, low gear ratio, underdrive to said driven shaft, and braking means selectively applicable to other elements of the several gear trains to activate the individual gear trains for the transmission of drive between said shafts, a drive ratio selector means, and output shaft speed responsive means 1 0. initiate all drive through the converter transmitted underdrive when the drive ratio selector means'has been ,setto activate the positive, low gear ratio, underdrive and to, thereafter automatically transfer the drive train to the positive underdrive gear train when the output shaft has attained a predetermined speed.

33.. A planetary type transmission mechanism adapted to be selectively driven by the impeller and turbine members of a hydraulic torque converter unit comprising a first shaft adapted to be drivin y connnected to said turbine, a second shaftadapted to be drivingly connected to said impeller, and anbutput shaft, said. first shaft mounting the sun gear of afirst planetary gear train and .the annulus gear of a second planetary train,said second shaft mounting the sun gear of a third planetary gear train, means connectingthe annulus gear of said first planetary gear train to said output shaft, means connecting the planetv carriers of said second and, third plan- .etary gear trains to said output shaft, brake means adapted to be applied to the planet carrier of said first planetary-gear train to activate said first train and provide means for transmitting a reverse drive from said first shaft to said output shaft, brake means adapted tobeapplied to the sun gear of said second planetary gear train to activate said second train and provide means for transmitting a forward underdrive from said first shaft to said output shaft, brake means adapted to be applied to the annulus gear of said third planetary gear train to activate-said third train and provide means for transmitting a for,- ward underdrive from said second shaft to said output shaft, a first clutch means adapted. to .drivingly connect said second shaft and said out put shaft to provide means for the transmission of direct drive between said clutch connected shafts, and a second clutch means adapted to drivingly'connect said second shaft to the annulus gear of said second planetary gear train to provide means for the transmission of a positive high speed underdrive. I

- JOSEPH JANDASEK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 2,456,328 Schneider Dec. 14, 1948 

